This is a work in progress….
https://developers.cloudflare.com/workers/examples/bulk-origin-proxy
https://developers.cloudflare.com/workers/examples/cors-header-proxy
Returning basics: https://developers.cloudflare.com/workers/examples/return-json
Suite of functions that can help (too prerolled but bits to copypasta) https://github.com/markusahlstrand/cloudworker-proxy